Spectrum-1 and Spectrum-2 do not have a per-TC counter of number of packets
marked by ECN. The value reported currently is the total number of marked
packets. Showing this value at individual TC Qdiscs is misleading.

Move the counter to ethtool instead.
Signed-off-by: NPetr Machata <petrm@mellanox.com>
Signed-off-by: NIdo Schimmel <idosch@mellanox.com>
Signed-off-by: NJiri Pirko <jiri@mellanox.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

Currently, only one SFN query is done from repetitive work at a time,
processing 64 entries. Another work iteration is scheduled in 100ms,
that means that the max rate of learned FDB entries is limited to 6400/s.
That is slow. Fix this by doing 2 optimizations:
1) Run 10 SFN queries at a time.
2) In case the SFN is not drained, schedule work with 0 delay to allow
   to continue processing rest of the records.

On a testing setup with 500K entries the time to process decreased
from 870secs to 10secs.
Signed-off-by: NJiri Pirko <jiri@mellanox.com>
Tested-by: NAlex Kushnarov <alexanderk@mellanox.com>
Signed-off-by: NIdo Schimmel <idosch@mellanox.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

The current codebase makes use of the zero-length array language
extension to the C90 standard, but the preferred mechanism to declare
variable-length types such as these ones is a flexible array member[1][2],
introduced in C99:

struct foo {
        int stuff;
        struct boo array[];
};

By making use of the mechanism above, we will get a compiler warning
in case the flexible array does not occur last in the structure, which
will help us prevent some kind of undefined behavior bugs from being
inadvertently introduced[3] to the codebase from now on.

Also, notice that, dynamic memory allocations won't be affected by
this change:

"Flexible array members have incomplete type, and so the sizeof operator
may not be applied. As a quirk of the original implementation of
zero-length arrays, sizeof evaluates to zero."[1]

Lastly, fix the following checkpatch warning:
CHECK: Prefer kernel type 'u32' over 'u_int32_t'
#61: FILE: drivers/net/ethernet/cisco/enic/vnic_devcmd.h:653:
+	u_int32_t val[];

This issue was found with the help of Coccinelle.

[1] https://gcc.gnu.org/onlinedocs/gcc/Zero-Length.html
[2] https://github.com/KSPP/linux/issues/21
[3] commit 76497732 ("cxgb3/l2t: Fix undefined behaviour")
Signed-off-by: NGustavo A. R. Silva <gustavo@embeddedor.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

The current codebase makes use of the zero-length array language
extension to the C90 standard, but the preferred mechanism to declare
variable-length types such as these ones is a flexible array member[1][2],
introduced in C99:

struct foo {
        int stuff;
        struct boo array[];
};

By making use of the mechanism above, we will get a compiler warning
in case the flexible array does not occur last in the structure, which
will help us prevent some kind of undefined behavior bugs from being
inadvertently introduced[3] to the codebase from now on.

Also, notice that, dynamic memory allocations won't be affected by
this change:

"Flexible array members have incomplete type, and so the sizeof operator
may not be applied. As a quirk of the original implementation of
zero-length arrays, sizeof evaluates to zero."[1]

This issue was found with the help of Coccinelle.

[1] https://gcc.gnu.org/onlinedocs/gcc/Zero-Length.html
[2] https://github.com/KSPP/linux/issues/21
[3] commit 76497732 ("cxgb3/l2t: Fix undefined behaviour")
Signed-off-by: NGustavo A. R. Silva <gustavo@embeddedor.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

The current codebase makes use of the zero-length array language
extension to the C90 standard, but the preferred mechanism to declare
variable-length types such as these ones is a flexible array member[1][2],
introduced in C99:

struct foo {
        int stuff;
        struct boo array[];
};

By making use of the mechanism above, we will get a compiler warning
in case the flexible array does not occur last in the structure, which
will help us prevent some kind of undefined behavior bugs from being
inadvertently introduced[3] to the codebase from now on.

Also, notice that, dynamic memory allocations won't be affected by
this change:

"Flexible array members have incomplete type, and so the sizeof operator
may not be applied. As a quirk of the original implementation of
zero-length arrays, sizeof evaluates to zero."[1]

This issue was found with the help of Coccinelle.

[1] https://gcc.gnu.org/onlinedocs/gcc/Zero-Length.html
[2] https://github.com/KSPP/linux/issues/21
[3] commit 76497732 ("cxgb3/l2t: Fix undefined behaviour")
Signed-off-by: NGustavo A. R. Silva <gustavo@embeddedor.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

The current codebase makes use of the zero-length array language
extension to the C90 standard, but the preferred mechanism to declare
variable-length types such as these ones is a flexible array member[1][2],
introduced in C99:

struct foo {
        int stuff;
        struct boo array[];
};

By making use of the mechanism above, we will get a compiler warning
in case the flexible array does not occur last in the structure, which
will help us prevent some kind of undefined behavior bugs from being
inadvertently introduced[3] to the codebase from now on.

Also, notice that, dynamic memory allocations won't be affected by
this change:

"Flexible array members have incomplete type, and so the sizeof operator
may not be applied. As a quirk of the original implementation of
zero-length arrays, sizeof evaluates to zero."[1]

This issue was found with the help of Coccinelle.

[1] https://gcc.gnu.org/onlinedocs/gcc/Zero-Length.html
[2] https://github.com/KSPP/linux/issues/21
[3] commit 76497732 ("cxgb3/l2t: Fix undefined behaviour")
Signed-off-by: NGustavo A. R. Silva <gustavo@embeddedor.com>
Acked-by: NMartin Habets <mhabets@solarflare.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

The current codebase makes use of the zero-length array language
extension to the C90 standard, but the preferred mechanism to declare
variable-length types such as these ones is a flexible array member[1][2],
introduced in C99:

struct foo {
        int stuff;
        struct boo array[];
};

By making use of the mechanism above, we will get a compiler warning
in case the flexible array does not occur last in the structure, which
will help us prevent some kind of undefined behavior bugs from being
inadvertently introduced[3] to the codebase from now on.

Also, notice that, dynamic memory allocations won't be affected by
this change:

"Flexible array members have incomplete type, and so the sizeof operator
may not be applied. As a quirk of the original implementation of
zero-length arrays, sizeof evaluates to zero."[1]

This issue was detected with the help of Coccinelle.

[1] https://gcc.gnu.org/onlinedocs/gcc/Zero-Length.html
[2] https://github.com/KSPP/linux/issues/21
[3] commit 76497732 ("cxgb3/l2t: Fix undefined behaviour")
Signed-off-by: NGustavo A. R. Silva <gustavo@embeddedor.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

Looks like the iavf code actually experienced a race condition, when a
developer took code before the check for chain 0 was put to helper.
So use tc_cls_can_offload_and_chain0() helper instead of direct check and
move the check to _cb() so this is similar to i40e code.
Signed-off-by: NJiri Pirko <jiri@mellanox.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

Return NULL instead of 0.
Signed-off-by: NSaeed Mahameed <saeedm@mellanox.com>
Reviewed-by: NMoshe Shemesh <moshe@mellanox.com>

drivers/net/ethernet/mellanox/mlx5/core/diag/fw_tracer.c:191:13:
sparse: warning: incorrect type in assignment (different base types)
Signed-off-by: NSaeed Mahameed <saeedm@mellanox.com>
Reviewed-by: NMoshe Shemesh <moshe@mellanox.com>

Clang warns:

 In file included from
 ../drivers/net/ethernet/mellanox/mlx5/core/main.c:73:
 ../drivers/net/ethernet/mellanox/mlx5/core/diag/rsc_dump.h:4:9: warning:
 '__MLX5_RSC_DUMP_H' is used as a header guard here, followed by #define
 of a different macro [-Wheader-guard]
 #ifndef __MLX5_RSC_DUMP_H
         ^~~~~~~~~~~~~~~~~
 ../drivers/net/ethernet/mellanox/mlx5/core/diag/rsc_dump.h:5:9: note:
 '__MLX5_RSC_DUMP__H' is defined here; did you mean '__MLX5_RSC_DUMP_H'?
 #define __MLX5_RSC_DUMP__H
         ^~~~~~~~~~~~~~~~~~
         __MLX5_RSC_DUMP_H
 1 warning generated.

Make them match to get the intended behavior and remove the warning.

Fixes: 12206b17 ("net/mlx5: Add support for resource dump")
Link: https://github.com/ClangBuiltLinux/linux/issues/897Signed-off-by: NNathan Chancellor <natechancellor@gmail.com>
Reviewed-by: NJason Gunthorpe <jgg@mellanox.com>
Signed-off-by: NSaeed Mahameed <saeedm@mellanox.com>

We can avoid an indirect call per compressed completion wrapping the
completion handling call with the appropriate helper.
Signed-off-by: NTariq Toukan <tariqt@mellanox.com>
Reviewed-by: NMaxim Mikityanskiy <maximmi@mellanox.com>
Signed-off-by: NSaeed Mahameed <saeedm@mellanox.com>

We can avoid an indirect call per NAPI cycle wrapping the RX descriptors
posting call with the appropriate helper.
Signed-off-by: NTariq Toukan <tariqt@mellanox.com>
Reviewed-by: NMaxim Mikityanskiy <maximmi@mellanox.com>
Signed-off-by: NSaeed Mahameed <saeedm@mellanox.com>

The current steps that are performed when the trust state changes, if
the channels are active:

1. The trust state is changed in hardware.

2. The new inline mode is calculated.

3. If the new inline mode is different, the channels are recreated using
the new inline mode.

This approach has some issues:

1. There is a time gap between changing trust state in hardware and
starting sending enough inline headers (the latter happens after
recreation of channels). It leads to failed transmissions and error
CQEs.

2. If the new channels fail to open, we'll be left with the old ones,
but the hardware will be configured for the new trust state, so the
interval when we can see TX errors never ends.

This patch fixes the issues above by moving the trust state change into
the preactivate hook that runs during the recreation of the channels
when no channels are active, so it eliminates the gap of partially
applied configuration. If the inline mode doesn't change with the change
of the trust state, the channels won't be recreated, just like before
this patch.
Signed-off-by: NMaxim Mikityanskiy <maximmi@mellanox.com>
Reviewed-by: NTariq Toukan <tariqt@mellanox.com>
Signed-off-by: NSaeed Mahameed <saeedm@mellanox.com>

Sometimes the preactivate hook of mlx5e_safe_switch_channels needs more
parameters than just struct mlx5e_priv *. For such cases, a new
parameter (void *context) is added to preactivate hooks.

Some of the existing normal functions are currently used as preactivate
callbacks. To avoid adding an extra unused parameter, they are wrapped
in an automatic way using the MLX5E_DEFINE_PREACTIVATE_WRAPPER_CTX
macro.
Signed-off-by: NMaxim Mikityanskiy <maximmi@mellanox.com>
Reviewed-by: NTariq Toukan <tariqt@mellanox.com>
Signed-off-by: NSaeed Mahameed <saeedm@mellanox.com>

Currently mlx5e_switch_priv_channels expects that the preactivate hook
doesn't fail, however, it can fail, because it may set hardware
parameters. This commit addresses this issue and provides a way to
recover from failures of the preactivate hook: the old channels are not
closed until the point where nothing can fail anymore, so in case
preactivate fails, the driver can roll back the old channels and
activate them again.
Signed-off-by: NMaxim Mikityanskiy <maximmi@mellanox.com>
Reviewed-by: NTariq Toukan <tariqt@mellanox.com>
Signed-off-by: NSaeed Mahameed <saeedm@mellanox.com>

The number of queues is now updated by mlx5e_update_netdev_queues in a
centralized way, when no channels are active. Remove an extra occurrence
of netif_set_real_num_tx_queues to prepare it for the next commit.
Signed-off-by: NMaxim Mikityanskiy <maximmi@mellanox.com>
Reviewed-by: NTariq Toukan <tariqt@mellanox.com>
Signed-off-by: NSaeed Mahameed <saeedm@mellanox.com>

Currently, mlx5e notifies the kernel about the number of queues and sets
the default XPS cpumasks when channels are activated. This
implementation has several corner cases, in which the kernel may not be
updated on time, or XPS cpumasks may be reset when not directly touched
by the user.

This commit fixes these corner cases to match the following expected
behavior:

1. The number of queues always corresponds to the number of channels
configured.

2. XPS cpumasks are set to driver's defaults on netdev attach.

3. XPS cpumasks set by user are not reset, unless the number of channels
changes. If the number of channels changes, they are reset to driver's
defaults. (In general case, when the number of channels increases or
decreases, it's not possible to guess how to convert the current XPS
cpumasks to work with the new number of channels, so we let the user
reconfigure it if they change the number of channels.)

XPS cpumasks are no longer stored per channel. Only one temporary
cpumask is used. The old stored cpumasks didn't reflect the user's
changes and were not used after applying them.

A scratchpad area is added to struct mlx5e_priv. As cpumask_var_t
requires allocation, and the preactivate hook can't fail, we need to
preallocate the temporary cpumask in advance. It's stored in the
scratchpad.

Fixes: 149e566f ("net/mlx5e: Expand XPS cpumask to cover all online cpus")
Signed-off-by: NMaxim Mikityanskiy <maximmi@mellanox.com>
Reviewed-by: NTariq Toukan <tariqt@mellanox.com>
Signed-off-by: NSaeed Mahameed <saeedm@mellanox.com>

mlx5e_ethtool_set_channels updates the indirection table before
switching to the new channels. If the switch fails, the indirection
table is new, but the channels are old, which is wrong. Fix it by using
the preactivate hook of mlx5e_safe_switch_channels to update the
indirection table at the stage when nothing can fail anymore.

As the code that updates the indirection table is now encapsulated into
a new function, use that function in the attach flow when the driver has
to reduce the number of channels, and prepare the code for the next
commit.

Fixes: 85082dba ("net/mlx5e: Correctly handle RSS indirection table when changing number of channels")
Signed-off-by: NMaxim Mikityanskiy <maximmi@mellanox.com>
Reviewed-by: NTariq Toukan <tariqt@mellanox.com>
Signed-off-by: NSaeed Mahameed <saeedm@mellanox.com>

mlx5e_safe_switch_channels accepts a callback to be called before
activating new channels. It is intended to configure some hardware
parameters in cases where channels are recreated because some
configuration has changed.

Recently, this callback has started being used to update the driver's
internal MLX5E_STATE_XDP_OPEN flag, and the following patches also
intend to use this callback for software preparations. This patch
renames the hw_modify callback to preactivate, so that the name fits
better.
Signed-off-by: NMaxim Mikityanskiy <maximmi@mellanox.com>
Reviewed-by: NTariq Toukan <tariqt@mellanox.com>
Signed-off-by: NSaeed Mahameed <saeedm@mellanox.com>

As a preparation for one of the following commits, create a function to
encapsulate the code that notifies the kernel about the new amount of
RX and TX queues. The code will be called multiple times in the next
commit.
Signed-off-by: NMaxim Mikityanskiy <maximmi@mellanox.com>
Reviewed-by: NTariq Toukan <tariqt@mellanox.com>
Signed-off-by: NSaeed Mahameed <saeedm@mellanox.com>

The LRO boolean state in params->lro_en must not be set in case
the NIC is not capable.
Enforce this check and remove the TODO comment.
Signed-off-by: NTariq Toukan <tariqt@mellanox.com>
Signed-off-by: NSaeed Mahameed <saeedm@mellanox.com>

We shall always extract channel index out of the txq, regardless
of the relation between txq_ix and num channels. The extraction is
always valid, as if txq is smaller than number of channels,
txq_ix == priv->txq2sq[txq_ix]->ch_ix.

By doing so, we can remove an if clause from the select queue method,
and have one flow for all packets.
Signed-off-by: NEran Ben Elisha <eranbe@mellanox.com>
Reviewed-by: NTariq Toukan <tariqt@mellanox.com>
Signed-off-by: NSaeed Mahameed <saeedm@mellanox.com>

Use the cookie index received along with the packet to lookup original
flow_offload cookie binary and pass it down to devlink_trap_report().
Add "fa_cookie" metadata to the ACL trap.
Signed-off-by: NJiri Pirko <jiri@mellanox.com>
Signed-off-by: NIdo Schimmel <idosch@mellanox.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

In case the received packet comes in due to one of ACL discard traps,
take the user_def_val_orig_pkt_len field from CQE and store it
in skb->cb as ACL cookie index.
Signed-off-by: NJiri Pirko <jiri@mellanox.com>
Signed-off-by: NIdo Schimmel <idosch@mellanox.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

Track cookies coming down to driver by flow_offload.
Assign a cookie_index to each unique cookie binary. Use previously
defined "Trap with userdef" flex action to ask HW to pass cookie_index
alongside with the dropped packets.
Signed-off-by: NJiri Pirko <jiri@mellanox.com>
Signed-off-by: NIdo Schimmel <idosch@mellanox.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

Expose "Trap action with userdef". It is the same as already
defined "Trap action" with a difference that it would ask the policy
engine to pass arbitrary value (userdef) alongside with received packets.
This would be later on used to carry cookie index.
Signed-off-by: NJiri Pirko <jiri@mellanox.com>
Signed-off-by: NIdo Schimmel <idosch@mellanox.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

Add cookie argument to devlink_trap_report() allowing driver to pass in
the user cookie. Pass on the cookie down to drop monitor code.
Signed-off-by: NJiri Pirko <jiri@mellanox.com>
Signed-off-by: NIdo Schimmel <idosch@mellanox.com>
Reviewed-by: NJakub Kicinski <kuba@kernel.org>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

The "stm32_pwr_wakeup" is optional per the binding and the driver
handles its absence gracefully. Request it with
platform_get_irq_byname_optional, so its absence doesn't needlessly
clutter the log.
Signed-off-by: NAhmad Fatoum <a.fatoum@pengutronix.de>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

The specification of a "eth-ck" and a "ptp_ref" clock is optional per
the binding and the driver handles them gracefully.
Demote the output to an info message accordingly.
Signed-off-by: NAhmad Fatoum <a.fatoum@pengutronix.de>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

If one types "failed to get enet clock" or similar into google
there are ~370k hits. The vast majority are people debugging
problems unrelated to this adapter, or bragging about their
rpi's. Further, the DT clock bindings here are optional.

Given that its not a fatal situation with common DT based
systems, lets reduce the severity so people aren't seeing failure
messages in everyday operation.
Signed-off-by: NJeremy Linton <jeremy.linton@arm.com>
Reviewed-by: NNicolas Saenz Julienne <nsaenzjulienne@suse.de>
Acked-by: NFlorian Fainelli <f.fainelli@gmail.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

ARM/ACPI machines should utilize self describing hardware
when possible. The MAC address on the BCMGENET can be
read from the adapter if a full featured firmware has already
programmed it. Lets try using the address already programmed,
if it appears to be valid.

It should be noted that while we move the macaddr logic below
the clock and power logic in the driver, none of that code will
ever be active in an ACPI environment as the device will be
attached to the acpi power domain, and brought to full power
with all clocks enabled immediately before the device probe
routine is called.

One side effect of the above tweak is that while its now
possible to read the MAC address via _DSD properties, it should
be avoided.
Signed-off-by: NJeremy Linton <jeremy.linton@arm.com>
Acked-by: NFlorian Fainelli <f.fainelli@gmail.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

The rpi4 is capable of booting in ACPI mode with the latest
edk2-platform commits. As such it would be helpful if the genet
platform device were usable.

To achieve this we add a new MODULE_DEVICE_TABLE, and convert
a few dt specific methods to their generic device_ calls. Until
the next patch, ACPI based machines will fallback on random
mac addresses.
Signed-off-by: NJeremy Linton <jeremy.linton@arm.com>
Acked-by: NFlorian Fainelli <f.fainelli@gmail.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

The unimac mdio driver falls back to scanning the
entire bus if its given an appropriate mask. In ACPI
mode we expect that the system is well behaved and
conforms to recent versions of the specification.

We then utilize phy_find_first(), and
phy_connect_direct() to find and attach to the
discovered phy during net_device open. While its
apparently possible to build a genet based device
with multiple phys on a single mdio bus, this works
for current machines. Further, this driver makes
a number of assumptions about the platform device,
mac, mdio and phy all being 1:1. Lastly, It also
avoids having to create references across the ACPI
namespace hierarchy.
Signed-off-by: NJeremy Linton <jeremy.linton@arm.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

The DT phy mode is similar to what we want for ACPI
lets factor it out of the of path, and change the
of_ call to device_.
Signed-off-by: NJeremy Linton <jeremy.linton@arm.com>
Acked-by: NFlorian Fainelli <f.fainelli@gmail.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

The current codebase makes use of the zero-length array language
extension to the C90 standard, but the preferred mechanism to declare
variable-length types such as these ones is a flexible array member[1][2],
introduced in C99:

struct foo {
        int stuff;
        struct boo array[];
};

By making use of the mechanism above, we will get a compiler warning
in case the flexible array does not occur last in the structure, which
will help us prevent some kind of undefined behavior bugs from being
inadvertently introduced[3] to the codebase from now on.

Also, notice that, dynamic memory allocations won't be affected by
this change:

"Flexible array members have incomplete type, and so the sizeof operator
may not be applied. As a quirk of the original implementation of
zero-length arrays, sizeof evaluates to zero."[1]

This issue was found with the help of Coccinelle.

[1] https://gcc.gnu.org/onlinedocs/gcc/Zero-Length.html
[2] https://github.com/KSPP/linux/issues/21
[3] commit 76497732 ("cxgb3/l2t: Fix undefined behaviour")
Signed-off-by: NGustavo A. R. Silva <gustavo@embeddedor.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

The current codebase makes use of the zero-length array language
extension to the C90 standard, but the preferred mechanism to declare
variable-length types such as these ones is a flexible array member[1][2],
introduced in C99:

struct foo {
        int stuff;
        struct boo array[];
};

By making use of the mechanism above, we will get a compiler warning
in case the flexible array does not occur last in the structure, which
will help us prevent some kind of undefined behavior bugs from being
inadvertently introduced[3] to the codebase from now on.

Also, notice that, dynamic memory allocations won't be affected by
this change:

"Flexible array members have incomplete type, and so the sizeof operator
may not be applied. As a quirk of the original implementation of
zero-length arrays, sizeof evaluates to zero."[1]

This issue was found with the help of Coccinelle.

[1] https://gcc.gnu.org/onlinedocs/gcc/Zero-Length.html
[2] https://github.com/KSPP/linux/issues/21
[3] commit 76497732 ("cxgb3/l2t: Fix undefined behaviour")
Signed-off-by: NGustavo A. R. Silva <gustavo@embeddedor.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

The current codebase makes use of the zero-length array language
extension to the C90 standard, but the preferred mechanism to declare
variable-length types such as these ones is a flexible array member[1][2],
introduced in C99:

struct foo {
        int stuff;
        struct boo array[];
};

By making use of the mechanism above, we will get a compiler warning
in case the flexible array does not occur last in the structure, which
will help us prevent some kind of undefined behavior bugs from being
inadvertently introduced[3] to the codebase from now on.

Also, notice that, dynamic memory allocations won't be affected by
this change:

"Flexible array members have incomplete type, and so the sizeof operator
may not be applied. As a quirk of the original implementation of
zero-length arrays, sizeof evaluates to zero."[1]

This issue was found with the help of Coccinelle.

[1] https://gcc.gnu.org/onlinedocs/gcc/Zero-Length.html
[2] https://github.com/KSPP/linux/issues/21
[3] commit 76497732 ("cxgb3/l2t: Fix undefined behaviour")
Signed-off-by: NGustavo A. R. Silva <gustavo@embeddedor.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

The current codebase makes use of the zero-length array language
extension to the C90 standard, but the preferred mechanism to declare
variable-length types such as these ones is a flexible array member[1][2],
introduced in C99:

struct foo {
        int stuff;
        struct boo array[];
};

By making use of the mechanism above, we will get a compiler warning
in case the flexible array does not occur last in the structure, which
will help us prevent some kind of undefined behavior bugs from being
inadvertently introduced[3] to the codebase from now on.

Also, notice that, dynamic memory allocations won't be affected by
this change:

"Flexible array members have incomplete type, and so the sizeof operator
may not be applied. As a quirk of the original implementation of
zero-length arrays, sizeof evaluates to zero."[1]

This issue was found with the help of Coccinelle.

[1] https://gcc.gnu.org/onlinedocs/gcc/Zero-Length.html
[2] https://github.com/KSPP/linux/issues/21
[3] commit 76497732 ("cxgb3/l2t: Fix undefined behaviour")
Signed-off-by: NGustavo A. R. Silva <gustavo@embeddedor.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

The current codebase makes use of the zero-length array language
extension to the C90 standard, but the preferred mechanism to declare
variable-length types such as these ones is a flexible array member[1][2],
introduced in C99:

struct foo {
        int stuff;
        struct boo array[];
};

By making use of the mechanism above, we will get a compiler warning
in case the flexible array does not occur last in the structure, which
will help us prevent some kind of undefined behavior bugs from being
inadvertently introduced[3] to the codebase from now on.

Also, notice that, dynamic memory allocations won't be affected by
this change:

"Flexible array members have incomplete type, and so the sizeof operator
may not be applied. As a quirk of the original implementation of
zero-length arrays, sizeof evaluates to zero."[1]

This issue was found with the help of Coccinelle.

[1] https://gcc.gnu.org/onlinedocs/gcc/Zero-Length.html
[2] https://github.com/KSPP/linux/issues/21
[3] commit 76497732 ("cxgb3/l2t: Fix undefined behaviour")
Signed-off-by: NGustavo A. R. Silva <gustavo@embeddedor.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>